1. Field of the Invention
The present invention relates to a method for manufacturing a nitride semiconductor laser device having a structure obtained by forming an n-type semiconductor layer, a light emitting layer and a p-type semiconductor layer (all made of group III nitride semiconductors, for example) on a group III nitride semiconductor substrate. The group III nitride semiconductors are group III-V semiconductors employing nitrogen as a group V element, and typical examples thereof include aluminum nitride (AlN), gallium nitride (GaN) and indium nitride (InN), which can be generally expressed as AlxInyGa1-x-yN (0≦x≦1, 0≦y≦1 and 0≦x+y≦1).
2. Description of Related Art
A semiconductor light-emitting device having a structure obtained by growing group III nitride semiconductor layers on a GaN substrate is known in general, and typical examples thereof include a blue light-emitting diode and a semiconductor laser. A semiconductor laser includes group III nitride semiconductor layers provided in a multilayer structure formed by successively stacking an n-type AlGaN cladding layer, an n-type GaN guide layer, an active layer (light emitting layer), a p-type GaN guide layer, a p-type GaN electron blocking layer, a p-type AlGaN cladding layer and a p-type GaN contact layer from a side closer to a GaN substrate, for example. The active layer has a multiple quantum well structure obtained by alternately repetitively stacking quantum well layers formed by InGaN layers and barrier layers formed by non-doped GaN layers, for example. According to this structure, electrons and positive holes are recombined in the active layer, to emit light. The emission wavelength can be adjusted by adjusting the In composition in the quantum well layers.